(a) Field of the Invention
This invention related to novel tropone derivatives, to processes for their preparation, to methods for using said derivatives, and to therapeutically acceptable salts and compositions of said derivatives.
More specifically, the present invention relates to novel tropone derivatives possessing valuable pharmacologic properties. For example, these derivatives are useful for preventing or treating allergic conditions in a mammal at dosages which do not elicit undesirable side effects. The combination of these pharmacologic properties renders the tropone derivatives of the invention therapeutically useful.
(B) Description of the Prior Art
A rather large number of reports dealing with tropone derivatives are available. The prior art relating to tropones is summarized in various reviews; for example, see the review by F. Pietra in Chem. Rev., 73, 293 (1973). In addition, other tropone derivatives are reported; for instance, a class of alkyl esters of 5-amidotropoles is described by L. D. Donaruma, Canadian Patent No. 787,451, issued June 11, 1968; N-troponyl amino acid esters are described in the Japanese Patent No. 24371/63, issued November 15, 1963; and (2-troponylthio)acetic acid is described by T. Nozoe et al., Proc. Japan Acad., 29, 22 (1953).
The tropone derivatives of the present invention are distinguished from the prior art compounds by the nature of the substituents on the tropone nucleus and by their pharmacologic properties.